ping主机查看是否处于连接状态

namespace Common 
...{ 
    using System; 
    using System.Net; 
    using System.Net.Sockets; 
    public class Ping 
    ...{ 
        const int SOCKET_ERROR = -1; 
        const int ICMP_ECHO = 8; 



        public static string PingH(string host,out bool isLink) 
        ...{ 
            isLink=false;
            string tmp="";
            IPHostEntry serverHE, fromHE; 
            int nBytes = 0; 
            int dwStart = 0, dwStop = 0; 
            Socket socket = 
                new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp); 
            socket.SetSocketOption(SocketOptionLevel.Socket,SocketOptionName.ReceiveTimeout,500);

            try 
            ...{ 
                serverHE = Dns.GetHostByName(host); 
            } 
            catch(Exception) 
            ...{ 
                Console.WriteLine("Host not found"); 
                return "Host not found"; 
            } 

            IPEndPoint ipepServer = new IPEndPoint(serverHE.AddressList[0], 0); 
            EndPoint epServer = (ipepServer); 

            fromHE = Dns.GetHostByName(Dns.GetHostName()); 
            IPEndPoint ipEndPointFrom = new IPEndPoint(fromHE.AddressList[0], 0); 
            EndPoint EndPointFrom = (ipEndPointFrom); 

            int PacketSize = 0; 
            IcmpPacket packet = new IcmpPacket(); 
            packet.Type = ICMP_ECHO; 
            packet.SubCode = 0; 
            packet.CheckSum = UInt16.Parse("0"); 
            packet.Identifier = UInt16.Parse("45"); 
            packet.SequenceNumber = UInt16.Parse("0"); 
            int PingData = 32; 
            packet.Data = new Byte[PingData]; 
            for (int i = 0; i < PingData; i++) 
            ...{ 
                packet.Data[i] = (byte)'#'; 
            } 

            PacketSize = PingData + 8; 
            Byte [] icmp_pkt_buffer = new Byte[ PacketSize ]; 
            Int32 Index = 0; 
            Index = Serialize( 
                packet, 
                icmp_pkt_buffer, 
                PacketSize, 
                PingData ); 
            if( Index == -1 ) 
            ...{ 
                Console.WriteLine("Error in Making Packet"); 
                return "Error in Making Packet"; 
            } 


            Double double_length = Convert.ToDouble(Index); 
            Double dtemp = Math.Ceiling( double_length / 2); 
            int cksum_buffer_length = Convert.ToInt32(dtemp); 
            UInt16 [] cksum_buffer = new UInt16[cksum_buffer_length]; 
            int icmp_header_buffer_index = 0; 
            for( int i = 0; i < cksum_buffer_length; i++ ) 
            ...{ 
                cksum_buffer[i] = 
                    BitConverter.ToUInt16(icmp_pkt_buffer,icmp_header_buffer_index); 
                icmp_header_buffer_index += 2; 
            } 
            UInt16 u_cksum = checksum(cksum_buffer, cksum_buffer_length); 
            packet.CheckSum = u_cksum; 

            Byte [] sendbuf = new Byte[ PacketSize ]; 
            Index = Serialize( 
                packet, 
                sendbuf, 
                PacketSize, 
                PingData ); 
            if( Index == -1 ) 
            ...{ 
                Console.WriteLine("Error in Making Packet"); 
                return "Error in Making Packet"; 
            } 


            dwStart = System.Environment.TickCount; 
            if ((nBytes = socket.SendTo(sendbuf, PacketSize, 0, epServer)) == SOCKET_ERROR) 
            ...{ 
                Console.WriteLine("Socket Error cannot Send Packet"); 
                return "Socket Error cannot Send Packet";
            } 
            Byte [] ReceiveBuffer = new Byte[256]; 
            nBytes = 0; 
            bool recd =false ; 
            int timeout=0 ; 

            while(!recd) 
            ...{ 
                try
                ...{
                    nBytes = socket.ReceiveFrom(ReceiveBuffer, 256, 0, ref EndPointFrom); 
                }
                catch(Exception ex)
                ...{
                    Console.WriteLine("Host not Responding") ; 
                    tmp="Host not Responding";
                    recd=true ; 
                    
                    break; 
                }
                if (nBytes == SOCKET_ERROR) 
                ...{ 
                    Console.WriteLine("Host not Responding") ; 
                    tmp="Host not Responding";
                    recd=true ; 
                    break; 
                } 
                else if(nBytes>0) 
                ...{ 
                    dwStop = System.Environment.TickCount - dwStart; 
                    Console.WriteLine("Reply from "+epServer.ToString()+" in " 
                        +dwStop+"MS :Bytes Received"+nBytes); 
                    tmp="Reply from "+epServer.ToString()+" in " 
                        +dwStop+"MS :Bytes Received"+nBytes;
                    recd=true; 
                    isLink=true;
                    break; 
                } 
                timeout=System.Environment.TickCount - dwStart; 
                if(timeout>1000) 
                ...{ 
                    Console.WriteLine("Time Out") ; 
                    tmp="Time Out";
                    recd=true; 
                } 
            } 

            socket.Close(); 
            return tmp;
        } 
        public static void PingHost(string host) 
        ...{ 
            IPHostEntry serverHE, fromHE; 
            int nBytes = 0; 
            int dwStart = 0, dwStop = 0; 
            Socket socket = 
                new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp); 

            try 
            ...{ 
                serverHE = Dns.GetHostByName(host); 
            } 
            catch(Exception) 
            ...{ 
                Console.WriteLine("Host not found"); 
                return ; 
            } 

            IPEndPoint ipepServer = new IPEndPoint(serverHE.AddressList[0], 0); 
            EndPoint epServer = (ipepServer); 

            fromHE = Dns.GetHostByName(Dns.GetHostName()); 
            IPEndPoint ipEndPointFrom = new IPEndPoint(fromHE.AddressList[0], 0); 
            EndPoint EndPointFrom = (ipEndPointFrom); 

            int PacketSize = 0; 
            IcmpPacket packet = new IcmpPacket(); 
            packet.Type = ICMP_ECHO; 
            packet.SubCode = 0; 
            packet.CheckSum = UInt16.Parse("0"); 
            packet.Identifier = UInt16.Parse("45"); 
            packet.SequenceNumber = UInt16.Parse("0"); 
            int PingData = 32; 
            packet.Data = new Byte[PingData]; 
            for (int i = 0; i < PingData; i++) 
            ...{ 
                packet.Data[i] = (byte)'#'; 
            } 

            PacketSize = PingData + 8; 
            Byte [] icmp_pkt_buffer = new Byte[ PacketSize ]; 
            Int32 Index = 0; 
            Index = Serialize( 
                packet, 
                icmp_pkt_buffer, 
                PacketSize, 
                PingData ); 
            if( Index == -1 ) 
            ...{ 
                Console.WriteLine("Error in Making Packet"); 
                return ; 
            } 


            Double double_length = Convert.ToDouble(Index); 
            Double dtemp = Math.Ceiling( double_length / 2); 
            int cksum_buffer_length = Convert.ToInt32(dtemp); 
            UInt16 [] cksum_buffer = new UInt16[cksum_buffer_length]; 
            int icmp_header_buffer_index = 0; 
            for( int i = 0; i < cksum_buffer_length; i++ ) 
            ...{ 
                cksum_buffer[i] = 
                    BitConverter.ToUInt16(icmp_pkt_buffer,icmp_header_buffer_index); 
                icmp_header_buffer_index += 2; 
            } 
            UInt16 u_cksum = checksum(cksum_buffer, cksum_buffer_length); 
            packet.CheckSum = u_cksum; 

            Byte [] sendbuf = new Byte[ PacketSize ]; 
            Index = Serialize( 
                packet, 
                sendbuf, 
                PacketSize, 
                PingData ); 
            if( Index == -1 ) 
            ...{ 
                Console.WriteLine("Error in Making Packet"); 
                return ; 
            } 


            dwStart = System.Environment.TickCount; 
            if ((nBytes = socket.SendTo(sendbuf, PacketSize, 0, epServer)) == SOCKET_ERROR) 
            ...{ 
                Console.WriteLine("Socket Error cannot Send Packet"); 
            } 
            Byte [] ReceiveBuffer = new Byte[256]; 
            nBytes = 0; 
            bool recd =false ; 
            int timeout=0 ; 

            while(!recd) 
            ...{ 
                nBytes = socket.ReceiveFrom(ReceiveBuffer, 256, 0, ref EndPointFrom); 
                if (nBytes == SOCKET_ERROR) 
                ...{ 
                    Console.WriteLine("Host not Responding") ; 
                    recd=true ; 
                    break; 
                } 
                else if(nBytes>0) 
                ...{ 
                    dwStop = System.Environment.TickCount - dwStart; 
                    Console.WriteLine("Reply from "+epServer.ToString()+" in " 
                        +dwStop+"MS :Bytes Received"+nBytes); 
                    recd=true; 
                    break; 
                } 
                timeout=System.Environment.TickCount - dwStart; 
                if(timeout>1000) 
                ...{ 
                    Console.WriteLine("Time Out") ; 
                    recd=true; 
                } 
            } 

            socket.Close(); 
        } 
        public static Int32 Serialize(IcmpPacket packet, Byte[] Buffer, 
            Int32 PacketSize, Int32 PingData ) 
        ...{ 
            Int32 cbReturn = 0; 
            int Index=0; 

            Byte [] b_type = new Byte[1]; 
            b_type[0] = (packet.Type); 

            Byte [] b_code = new Byte[1]; 
            b_code[0] = (packet.SubCode); 

            Byte [] b_cksum = BitConverter.GetBytes(packet.CheckSum); 
            Byte [] b_id = BitConverter.GetBytes(packet.Identifier); 
            Byte [] b_seq = BitConverter.GetBytes(packet.SequenceNumber); 

            Array.Copy( b_type, 0, Buffer, Index, b_type.Length ); 
            Index += b_type.Length; 

            Array.Copy( b_code, 0, Buffer, Index, b_code.Length ); 
            Index += b_code.Length; 

            Array.Copy( b_cksum, 0, Buffer, Index, b_cksum.Length ); 
            Index += b_cksum.Length; 

            Array.Copy( b_id, 0, Buffer, Index, b_id.Length ); 
            Index += b_id.Length; 

            Array.Copy( b_seq, 0, Buffer, Index, b_seq.Length ); 
            Index += b_seq.Length; 

            Array.Copy( packet.Data, 0, Buffer, Index, PingData ); 
            Index += PingData; 
            if( Index != PacketSize/**//* sizeof(IcmpPacket) */) 
            ...{ 
                cbReturn = -1; 
                return cbReturn; 
            } 

            cbReturn = Index; 
            return cbReturn; 
        } 
        public static UInt16 checksum( UInt16[] buffer, int size ) 
        ...{ 
            Int32 cksum = 0; 
            int counter; 
            counter = 0; 

            while ( size > 0 ) 
            ...{ 
                UInt16 val = buffer[counter]; 

                cksum += Convert.ToInt32( buffer[counter] ); 
                counter += 1; 
                size -= 1; 
            } 

            cksum = (cksum >> 16) + (cksum & 0xffff); 
            cksum += (cksum >> 16); 
            return (UInt16)(~cksum); 
        } 
    } 
    public class IcmpPacket 
    ...{ 
        public Byte Type; 
        public Byte SubCode; 
        public UInt16 CheckSum; 
        public UInt16 Identifier; 
        public UInt16 SequenceNumber; 
        public Byte [] Data; 

    } 
}